The half-life of sodium-24 is _ which is used to estimate the volume of blood in a patient.
Correct answer: B. 15 hours
- A. 6 hours
- B. 15 hours
- C. 8 hours
- D. 15 days
Explanation
Sodium-24 is a radioactive isotope of sodium with a half-life of approximately 15 hours. This means that if a sample of sodium-24 contains 1000 atoms, after 15 hours, only 500 atoms will remain.The radioactive decay of sodium-24 can be used to estimate the volume of blood in a patient. This involves injecting a small amount of sodium chromate, which contains sodium-24, into the patient's bloodstream. As the sodium-24 decays, it is eliminated from the body through the urine. By measuring the rate at which sodium-24 is excreted in the urine, the volume of blood in the patient's body can be estimated.
This question appeared on the UHS MDCAT 2012 paper, which you can sit online with every answer explained.
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